De-esterification and transacylation reactions of pectinesterase from jelly fig (Ficus awkeotsang Makino) achenes

Pectinesterase (PE) was isolated from jelly fig (Ficus awkeotsang Makino) achenes, then the optimal conditions for de-esterification and transacylation reactions were determined. Molecular weight of pectin (DE=62.8%) when reacted with PE at PH 6.5 and 45 degreesC in 0.2 M NaCl for 20 min remarkably increased from the original 72 kDa to 410 kDa, as determined by Fractogel TSK 65(S) gel permeation chromatography. Prolonging the incubation time of pectin-PE mixtures to 2 and 4 h also increased the molecular weights of pectin. Therefore, transacylation reaction was considered to occur and to increase the molecular weight of pectins when de-esterification reaction was catalyzed by pectinesterase (PE).